racer: add pkg and vim plugin

pkgs/development/tools/rust/racer/default.nix

@@ -0,0 +1,29 @@
+{stdenv, fetchgit, rust, makeWrapper }:
+
+let
+  rustSrc = rust.src;
+in
+
+stdenv.mkDerivation rec {
+  #TODO add emacs support
+  name = "racer-git-2014-11-24";
+  src = fetchgit {
+    url = https://github.com/phildawes/racer;
+    rev = "50655ffd509bea09ea9b310970dedfeaf5a33cf3";
+    sha256 = "0bd456i4nz12z39ljnw1kjg8mcflvm7rjql2r80fb038c7rd6xi1";
+  };
+
+  buildInputs = [ rust makeWrapper ];
+
+  installPhase = ''
+    mkdir -p $out/bin
+    cp -p bin/racer $out/bin/
+    wrapProgram $out/bin/racer --set RUST_SRC_PATH "${rustSrc}/src"
+  '';
+
+  meta = {
+    description = "A utility intended to provide rust code completion for editors and IDEs.";
+    homepage = https://github.com/phildawes/racer;
+    license = stdenv.lib.licenses.mit;
+  };
+}